DE2161310C3 - Process for at least partial separation of solid particles distributed in a liquid with the aid of gravity and a device for carrying out the process - Google Patents

Description

The invention relates to a method for at least partially separating in a liquid distributed solid particles with the help of gravity, in which the mixture in at least two successive Separate stages, in each stage the separated solid particles as well as those on them depleted liquid is guided along an inclined collecting surface and thereby the horizontal component the migration speeds in adjacent stages with regard to their direction be rotated more than 90 °, as well as a device for performing this method with a feed for the clarifying medium and at least one drain each for the excreted material and the clarified or partially clarified clarifying medium, at least partially in the flow path of the clarifying medium

seen, the inclination reverses from one plate to the next.

In a known clarifier of this type, horizontal plates are used to deflect the passing through Clarification medium and intended for the deposition of the solid component. You are at two fixed opposite device walls,

storage work. In the meantime, in these devices, too, the slipping sediment and the rising flow of the clarifying medium intersect. The present invention is therefore based on the object of providing a method of the type mentioned at the outset Art to develop and to create a device for performing this process, with which or with their help a flawless, interference sources

Plates that are inclined to the vertical are arranged as well as the unclarified or partially and, in the direction of flow of the sewage material, ascending sewage material is a result. Out

"~" T "» n Hu-Nrfaiin. ν ™,.; "» ,. DW- * _u -.-_ for this reason this device is for clarification

Clarifying media with a high proportion of solids are not suitable, 5 as the solid particles that slide off are tubular Approaches would clog up pretty soon. This device is primarily used to separate differently heavy liquids.

Furthermore, clarifying cder separation

namely alternately once on one and one io devices proposed, which with ancillary

times on the opposite wall. The free, mutually arranged plate shares for the

Plate ends overlap, and besides, they are _. . · _.- - _ ·. u ,: angled downwards in one variant. The clarified material runs through this device
a zigzag path, with 15
on the horizontal part of the plate over time
deposit more and more solid particles. To remove the separated material from the rter device
from time to time, the panels will turn into a

Brought tilted position, whereby the clarification of the clarifying medium which avoids them is possible. stored good slides down and over a The initially outlined type attached to the lowest point of the device suggested which he-opening can be deducted. The clarifying medium according to the invention is characterized in that the is fed at the bottom of the device, and the mixture in each stage in a number of under-clarified Liquid is drawn from the upper device, which is essentially parallel or equivalent to one another away. This device has the disadvantage of being separated from the designed separating spaces that only an intermittent operation is possible with it. In addition, the one descending from the inclined surfaces crosses the separating space of one of the steps part of the deposited material slipping off the component in one of two neighboring Scheidedes upward flowing medium and will clear this 30 while the subsequent stage occurs thus, in an undesirable manner, the oppositely rising component of this again and again mixed. Furthermore, in this device there is an adjacent separating chamber of the following stage their low separation efficiency is disadvantageous. There are deans in the same separating room of the previous level animal devices have become known, which flows with a and thereby the layer of migratory festivities Flock of parallel deposition plates 35 particles of material over the entire width of their wall work. In one case, the medium to be clarified is circulated.

at the top, at the other at the bottom. After the downward wandering

In both cases, however, the material changing from the sloping crosses over the entire width,

Solid content of the clarifying medium slipping off the plates, so it spares him a path through a narrow point,

the ascending or less clarified medium. 40 the risk of clogging is averted. A verse

As with the previously described premixing of the particles that have already settled with the direction, this leads to an ever new admixture and
thus to a relatively poor efficiency of the
Contraption.

In a further device one has tried to eliminate this disadvantage by 45 the clarifying medium leads in zigzag-like channels. The bottom of each channel

is connected with a vertically downwardly directed tube

provided, the solidification increasing as deep as possible into the upper 50 sewage material to a schheß end of the following channel protrudes. Also there were hardly any bodies that could migrate. Through With this device, the medium to be clarified becomes the rearrangement of the material again and again fed. Accordingly, it wanders from below, loosened, without it being the ascending one because of it upwards, whereby the heavier component medium would be mixed in. This gets deposited at the bottom of each channel. The lighter grain has a relatively high migration speed component migrates to the top of the duct. If by the end of the trail. The finally the concentration of the separated medium now deposited from a higher-lying channel Parts slide downwards, this is by no means less than with other methods, the tubular extension through, whereby the This is important as the ejected good downward and the upward moving stream at the 60 is often further processed, for example relevant Cross the place, but both are pressed through. These presses are relatively more expensive Pipe itself are separated from each other. In this way it is in the least possible fluid way because of it an admixture of the deposited material is important for the material to be pressed out. In order to the high-flow clarification medium, at least at this point, is then also the performance of the press system Place prevented. The disadvantage of this device 65 is increased.

lies in the fact that the device cross-section at the In a particularly preferred embodiment

relevant body is split into two parts. the procedure is declining when settling

It thus arises for both the slipping and rising liquid in at least the constituents

ascending medium is prevented by the fact that the two partial flows along the entire flow path be guided parallel to each other.

Furthermore, a significantly reduced throughput time is achieved without reducing the degree of clarification in that the goods are shifted from one group to the next. One prevents thereby in the direction of passage of the deposited

intercepted a stage and led in the direction of the entering Rohgemisoh.

The device according to the invention is characterized in that several plates are spaced apart to form flow channels are arranged, with the plates of one group in each case with a gap in relation to the plates of the next group are set and the plate underside guide surfaces for the ascending medium part and the plate tops Form guide and deposit surfaces for the sinking part of the medium.

This device permits the method according to the invention described in detail at the beginning without any problems perform.

Some exemplary embodiments of the invention are described below with reference to FIGS. 4 to 14 of the Drawing illustrated embodiments explained in more detail. In the drawing shows in schematic reproduction

F i g. 1 a vertical sedimentation vessel, FIG. 2 an inclined sedimentation vessel, F i g. 3 the accumulation of the sunken material in an inclined sedimentation vessel,

4 shows a separation device according to the invention,

F i g. 5 and 6 profile shapes of collecting surfaces, F i g. 7 and 8 the redeployment mechanism, Fi g. 9 shows the formation of a flow of liquid along the top generatrix of an inclined pipe.

10 shows a further embodiment of the invention,

11 and 12 are views of the collecting surfaces with the viewing direction A and B according to FIG. 10,

13 schematically shows a further embodiment of the invention,

14 shows the diagram of an application of the invention Device in connection with a round thickener.

If, in a vertical vessel, a particle P, which is at a certain level H above the vessel bottom at time t - 0, reaches it after time T according to Stokes' law (FIG. 1), such a particle reaches the bottom of an inclined vessel (FIG. 2) in a time τ which is generally less than T. In the inclined vessel (Fig. 2) the height of fall in the liquid is smaller than in the vertical one, the sinking path is obviously less, and therefore the sinking time is 1 1 less than T. , ^; n the course of which the particles slide on the vessel wall. The following applies: τ = / 1 -j- 12. In the case of thin turbidity and fine grain sizes, 11 is negligible compared to 1 1, and the sedimentation times can be shortened if the turbid body is divided into numerous layers, which are delimited by inclined, parallel walls. If, however, a thickening is sought, the situation is different, and ti becomes more relevant the more the solids concentration increases.

In inclined pipes, from a certain concentration on, they form on and in the vicinity of the collecting trays Tongues off (Fig. 3). The greatest friction occurs in the area adjacent to the settling surface Particle layer on while at the same height level in the vicinity of the upper pipe wall zone the sediment remains loosened.

Because of the high concentration on the underside of the layer, sliding comes to a standstill here, and what is more, the overlying, still luring sinking material is considerably slowed down. Under these circumstances, the sum of the times rl and ti would be as large or greater than T, and the advantages that could be achieved with the use of inclined layers disappear because the shortening of the sedimentation time is not in itself decisive.

The illustrated in Fig. 4, a settling basin performing device has a cuboid

»Ο Trough 1 with funnel-shaped bottom 2 on which An outlet 3 is set at the lowest point. In the vicinity of the upper edge of a side wall 4 is an inlet channel 5, an outlet channel 7 with an outlet S near the edge of the opposite side wall 6

«5 arranged. The side wall edges 9 and 10 or the upper edges of the grooves 5 and 7 protruding towards the inside of the trough for reasons of better space utilization form an overflow for the raw mixture R fed in at 5 and an overflow for

• β separated liquid. Below the discharge channel 7 is a shut-off element 11, such as a valve or slide, intended. The part of the trough interior located above the shut-off element 11 does not contain any binbauten. In the from the point of attachment of the soil 2

»5 to a point just below the shut-off element 11 The level reaching part of the trough interior are accommodated, for example, in four groups I to IV are combined. Each of these flocks arranged one above the other

contains a number of collecting surfaces 12 or 13 to 15, which are each parallel to one another, with the horizontal sliding or inclination angle λ. to V or with the perpendicular include the corresponding complementary angle / ?, to ft ₄ and can be designed as essentially flat sheets or as profiled sheets with a relatively shallow profile (F, g 5 and 6). It is recommended that the

Pmc ΓΊ? ^{d% outermost} collecting surfaces with the respective trough side walls 4 and 6 to ver -:.!.!?, ^{"U d so} ^ provide surfaces 16 and 17 to ne 18 to keep small Of the up 15 vagina spaces 19 to the.. collecting surfaces of each family are 4, Hnri, n _"f ι -I ^benachba rten flock or flock to" ° "f ^onta 'nchtung offset so that the Distinctive η, ^9FL - ^{emer coulter' z} · ^B · ^saddle 'I. AusrTumen i ^ "^ ' ^{each with} ™ ^ei Scheideode? * ha? ^{fl and 20fe} 'of ^the neighboring group of ^ ™^; The collecting surfaces each have inclinations ver ' , ie the inclinations are effective 31 in succession, e.g. B. 12 and 13, match-B. I and Π each lie one through the of the

p 15 m »/ b

^{from a} > solid-being ^{8 to emen of 20} ° fi / ¹ _iC kt

The thickening can, for. B. also on a FcMrtoff-

(ο

Hall can be increased by 300 g / l, which, however, goes hand in hand ^{with a considerable decrease in the throughput rate, namely to 3 m s / h.} This disadvantage is eliminated in settling basins equipped according to the invention, with which the same final concentration can be achieved with a significantly higher throughput with the same size and with four groups of collecting areas. It is advisable to measure the sliding angles α or the complementary angles / i, - (/ = 1, 2, 3 ...) differently from one another, namely

to be selected so that the collecting areas are increasingly inclined relative to the horizontal in accordance with their surface loads, which increase from flock to flock. It has proven to be advantageous for the angle β, the condition 35 °; g / J, <; 70 ^J must be observed. For example, the top coulter I can be 70 cm high, the angle / ■ ;, 55 and the distance between the collecting surfaces 12 can be 12 cm, while the angles / i. "/?." / F ₄ equal 45, 35, 25 ° and the collecting surfaces 13, 14 and 15 are dimensioned correspondingly larger. With such a settling basin, the desired final concentration of 300 g / l can still be achieved at a throughput of 15 m ^s / h, i.e. the volume output per unit of time compared to the built-in-free trough can be increased fivefold without requiring more space. This increase is due to the enlargement of the effective settling area and, above all, to the reallocation of the migrating material achieved during the transition from one to the next separation area.

The redeployment mechanism is shown in FIGS. 7 and 8 illustrate, from which it can be seen how the stratification of the material migrating along a collecting surface is rendered ineffective at the joint between adjacent groups. The grain that has reached the collecting surface 12 or 14 and is already in the vicinity of its lower edge to form a relatively tightly packed layer that is not very slippery falls over the lower edge into the adjoining separating space without penetrating the liquid that is in this separating space the goods that have sunk there, i.e. without disturbing the separation that has taken place there. However, the stratification will certainly be destroyed, because the layer next to the collecting surface 12 or 14 by no means reaches the collecting surface 13 or 15, but must first reassemble, which because of the considerable concentration takes place slowly, ie at a distance from the The transition point begins. The lower edge of the collecting surfaces 12 and 14 and the upper edge of the collecting surfaces 13 and 15 are essentially in a common horizontal plane and are offset from one another by horizontal distances, 1,, and / f ₍₂ , where

I ₁₁ f A ₁ .

d,
cos /? «

, ι - 1.2.3.4

is applicable. Here, a _{k is} the shortest distance between adjacent collecting areas of a flock. It can be recommended, especially in the lower-lying families III, IV ... (/ - 3, 4 ...), the distances 1 _{/ f} and .I ₁ -. to adjust the height of the goods moving in the relevant separation space and accordingly _{to select J / t} > -d _{; 2} (see Fig. 8), so that a larger transport cross-section is available for this good with the same dimensions of the device.

A movement of the liquid is associated with the displacement of the sinking solid particles, which is displaced by the sinking particles, a process that is more or less stationary. and none at low concentrations, at the

ίο the high concentrations aimed for, however, very well can be of practical importance.

A relatively thick kaolin suspension colored with potassium permanganate is placed in a tubular A vessel, the axis of which encloses an angle of 30 ° with the vertical, is very evident soon one of the f i g. 9 corresponding picture. Even at a small distance above the ground, it begins to appear Form a flow path which runs essentially along the uppermost generatrix of the tube.

ao The water, which appears dark, rises unhindered along this flow path. Be in tune with the invention collecting surfaces with a z. B. roof-shaped or wave-shaped longitudinal fluting is used (Fig. 5, 6), this measure not only leads to a measure that is desirable in deeper flocks and material-saving stiffening of these surfaces, but also causes them to emerge Flow paths in which the liquid is practically without affecting the sedimentation process can rise upwards without resistance because, due to the inclination, the height at which the Fluid movement is hindered by the particles present is much less.

The one above the shut-off element 11 (FIG. 4) Part of the trough interior forms a clarification room free of built-in components, because the one located there Due to its low concentration, there is still no noticeable reduction in the speed of fall of the individual solid particles due to mutual hindrance.

The raw mixture R fed continuously or at time intervals into the feed channel 5 experiences a pre-thickening in the upper part of the trough interior and has at the level of the shut-off

organs 11 reaches a concentration at which the collecting surfaces arranged according to the invention become effective. That went down over these areas No good emerges from the trough via its outlet 2, whereas the liquid in continuous Operation via the outlet channel 7 and the outlet 8 in the case of discontinuous operation through the shut-off organ 11 is removed because at its approach place because of the occurring Horizontalschlämmunj the solids concentration between the trapping

surface rising liquid is reached.

A modified version is recommended for thickening pulp with higher starting concentrations The second device, which can be taken from Fig. 10, ii its cuboid trough 23 up to the level:

of the supplied raw mixture R or the liquid discharged one on top of the other, sets I to I \, etc. of collecting surfaces are arranged so that π the entire trough interior transport routes for the settled, migrating goods are provided.

Experience has shown that the speed of the rising at the bottom of the collecting surface Liquid, especially in the area of the upper families, can become so turbulent

409638/191

Flow zones arise that disrupt the settling process. Will the ascending liquid from the Separation rooms in which a separation takes place, diverted and directed towards a harmless place, so this danger is averted. In contrast to the embodiment according to FIG. 4 are the collecting surfaces therefore normal to the trough side walls 24 and 25, on which the inlet channel 26 and the Drainage channel 27 are arranged.

Both the inlet and the drainage channel are connected to the trough interior via perforated partition walls such as sheets or wire nets 44 or 45 in connection and extend over different Heights, namely the inlet channel 26 over the height of two shares (I and 'I) and the drainage channel 27 only about the height of a flock (I).

The rising liquid can be caught and drained off in a very simple manner with the aid of guide strips or strips 29, which are placed on the collecting surfaces 28 and run obliquely over them.

In this way, the liquid is directed into a gap between the inlet-side trough side wall 24 and the collecting surfaces, in which it rises and arrives at the point at which the raw mixture enters and no separation takes place. In most cases it is sufficient if the collecting surfaces 28 of the coulter III located immediately below the inlet channel 26 are each provided with a guide strip 29 which runs from the upper inlet-side corner to the outlet-side lower corner of each collecting surface, along its upper longitudinal edge is at least locally attached and forms an angle with it, e.g. B. hangs vertically. FIGS. 11 and 12 show this arrangement in views of FIG. 10 with viewing direction A and B. The effectiveness of the drainage of ascending liquid from zones important for the separation process was shown in a comparative test. When a clay pulp was thickened in a device of the structure described, but without the arrangement of a guide strip, the liquid overflow emerging from the discharge channel 27 contained 1.5 g / l clay substance. After installing the strips 29, the clay content dropped to 0.1 g / l. 13 shows a further embodiment of the device according to the invention. In practice, the separation systems are always required to have high throughputs. However, the flow velocity must not become too great, because otherwise turbulence would occur and reduce the effectiveness of the cutting process. By using large settling areas, ie

numerous collecting areas, the flow speed can be kept low. A twin system of the type shown schematically in FIG. 13 has proven to be very useful for clarifying and thickening pulp. The trough 46 has an overflow channel 47 for the liquid on each of two opposite side walls and an inlet 48 for the raw mixture in the middle between these two walls, which is provided with two essentially parallel perforated plates 49 or, preferably reaching as far as the trough bottom. Like. Is provided. In both of these sheets and α ⁿ "n ^{gseitenwänden} limited chambers collecting surfaces flocking I to IV analogous to FIG. 4

or IO housed. The incoming raw sludge R is evenly distributed over the entire cross-sections of the shares I to IV, whereby the flow rate - compared with simple systems - with the same throughput with simple means

amount is halved.

An operational example of the application of the device according to the invention will now be given with reference to FIG. in connection with a round thickener explained.

< ^D n ^Ru " ^{de thickness} r50 with a raking device, the diameter of which is 20 m, is charged, for example, with 300 m'.h of wastewater from a used sand recovery plant of a foundry

Solid content of 5 g / l. Clear wastewater can be achieved by adding flocculation. ΓΪ V ^e; i ^{2 runs' of the} can Sinkgutauslauf p / hrfh, but are not brought ^rahlbewe supply over 100 g of 1 K.

This sewage treatment plant is ^{coupled to a Basier 8} ™ ^ ³ v ^{according to Fi} S · ⁴ according to the invention, whose

fön on · ³ A ° ^m u ^is - ^{The sink} S ^ut Ο * ^{m3 h with} 100 g, 1) w, rd fed into the inlet 5 via a pump 53.

The purpose of the device according to the invention is, in _{combination with diP W,} only on thickening

The now settled to 200 g / l, how ^ i? ^ft ' ^b ? ³ ^ ^{depends Inv} estitions- and loading

With
fen

³ itions and Be

^ · Κ ^a "achgeschaltete suction Trubeüberlauf vaginal device f ^ver enlarges the load on the ^

^{11 only u} « ³

For this purpose 4 sheets

Claims (10)

Patent claims: 1. A method for at least partially separating solid particles distributed in a liquid with the help of gravity, in which the mixture in at least two consecutive Separate stages, in each stage the separated solid particles as well as the this depleted liquid is guided along an inclined collecting surface and thereby the horizontal components the migration speeds in neighboring stages are rotated by more than 90 ° in terms of their direction, characterized in that the mixture, in each stage in a number of one another is separated essentially parallel and identically shaped separating spaces, at the Transition point of successive steps in each separating space of the one step downwards migrating component in one of two adjacent separation chambers (20 a) of the following Stage (II) occurs while the oppositely rising component of that adjacent to it Separation space (206) of the subsequent stage (II) in the same separation space (19a) of the previous stage (I) flows and thereby the layer of migrating solid particles over the entire width of their migration path is circulated. 2. The method according to claim 1, characterized in that when settling descending Constituents rising liquid caught in at least one stage and in the direction is performed on the incoming raw mixture. 3. Apparatus for performing the method according to claim 1 or 2 with a feed for the clarifying medium and at least one drain each for the excreted material and the clarified or partially clarified clarifying medium, with at least in the flow path of the clarifying medium partially inclined to the vertical are arranged plates and extend in the direction of passage of the clarified material, the inclination from one plate to the next reverses, thereby characterized in that several plates (e.g. 12) with are arranged at a mutual distance, the plates (z. B. 12) of a flock (I) each on Gap opposite the plates (e.g. 13) of the next coulter (II) and the undersides of the plates Guide surfaces for the rising part of the medium and the top of the plates Guide and deposit surfaces for the sinking part of the medium. 4. Apparatus according to claim 3, characterized in that the lower and upper edges the collecting surfaces of the upper or lower of two adjacent groups into a common Level or are each laid in one of two parallel horizontal planes, preferably the level of the lower margins is just below the level of the upper margins. 5. Apparatus according to claim 3 or 4, characterized in that the passage gap (A _n ) for migrating material is wider than the passage gap (J ₁₂ ) for ascending liquid. 6. Device according to one of claims 3 to 5, characterized in that the angle of inclination (X ₁ ; Ct ₄ ) of the collecting surfaces (12) of at least one group (I), but preferably each group, is smaller than the angle of inclination (a ₂ ; a _f ,,) of the collecting surfaces (13) of the coulter (H) immediately below is dimensioned and these angles of inclination are between 35 and 70 °. 7. Device according to one of claims 3 to 6, characterized in that the collecting surfaces have a steeper edge strip on at least one of their edges. 8. Device according to one of claims 3 to 7, characterized in that the in the cuboid-shaped, on a side wall (24) with an inlet for the raw mixture, on the opposite side wall (25) with an outlet for the liquid and with a bottom, at the lowest point of which there is a Sinkgutauslaß, provided trough (23) accommodated collecting areas (28) as compared to these sides (24, 25) essentially normal the horizontal inclined panels are designed and on each collecting surface (28) at least coulter (III) located directly below the inlet channel (26), preferably by means of a coulter attached to it attached, e.g. B. perpendicular, drooping guide strip (29) each have a discharge channel for ascending Liquid is formed along this collecting surface (28) against the inlet side End rises, which is arranged at a distance from the trough side wall (24). 9. Apparatus according to claim 8, characterized in that the inlet and the liquid outlet than communicating with the inside of the trough via a perforated partition wall (44, 45) Grooves (26, 27) are formed and in which the height of the inlet-side perforated Intermediate wall (44) corresponding trough section at least one share (I, II) is arranged. 10. Apparatus according to claim 9, characterized in that the lower edge of the inlet side perforated partition (44) deeper than the lower edge of the outlet-side perforated Intermediate wall (45) lies.